1. Field of the Invention
The present invention relates to a panel light source device and a fabrication process for the same, more particularly to improvement on a panel light source device and a fabrication process for the same, which is used in a display device for mainly presenting letters, an image and others thereon, for example a liquid crystal display device.
2. Description of the Related Art
A liquid crystal display device has features such as being slim, light, low in power consumption and others in comparison with other kinds of display devices, and has been widely used as display devices for use in various applications such as those starting with a computer, followed by portable terminals including a portable telephone, a car navigation terminal and others. In a case of a liquid crystal display device, since a liquid crystal panel on which image information on each pixel is reproduced does not emit light by itself, a light source device is required additionally, so that a liquid crystal display device is commonly equipped with a light source device called a back light device emitting light at a rear face side of a liquid crystal panel.
In such a display device, since there is necessity that a display region for an image or the like is illuminated uniformly by light, there has been a demand for a panel light source device, having a light emitting surface corresponding to the display region, and being excellent in uniformity of a light emitting characteristic on the light emitting surface. Furthermore, a request has been made for downsizing and weight reduction of the light source device in order to realize downsizing and weight reduction of the light display device as a whole. For this reason, in this kind of a light source device, a side light type has been commonly adopted in which a linear shaped light emitter is disposed at the side-face side of a light guide plate.
FIG. 9 is a sectional view showing a construction of a conventional panel light source device, showing an example of a liquid crystal display device with a back light device adopting a side light type. In the figure, a numerical reference 1 indicates a light guide plate, 2 an optical sheet, 3 a light emitter, 4 a wire, 5 a reflecting sheet, 6 a front face case, 7 a rear face case and 12 an opening section. The constituents 1 to 5 are housed in a composite case formed by engaging the front face case 6 and the rear face case 7 with each other to construct a panel light source device and a liquid crystal panel 10 is mounted outside the opening section 12 of the panel light source device to construct a display device.
In order to realize downsizing and weight reduction of the light source device, the reflecting sheet 5 is provided not only on the rear face side of the light guide plate 1, but also used as a lamp reflector obtained by bending an end portion in the light emitter 3 side into the shape of a Greek letter Π open sideways and light emitted from the light emitter 3 strikes an light incident face provided at a side face of the light guide plate 1. An end portion in the wire 4 side of the reflecting sheet 5 is bent into the shape of an erected L to reflect light emitting through a side face of the light guide plate 1 thereon and to thereby prevent leakage of the incident light from the light emitter 3 through the side face of the light guide plate 1 opposite to the light incident face. Hence, the incident light from the light emitter 3 exits from the front face of the light guide plate 1 (the optical sheet 2 side). The light leaving the front face is emitted through the opening section 12 through the optical sheet 2 and the opening section 12 works as a light emitting surface.
FIG. 10 is a sectional view showing a way of assembly of the panel light source device of FIG. 9. The reflecting sheet 5 is at first housed in the rear face case 7 and thereafter, the light emitter 3 and the wire 4 are housed. The wire 4 is a power supply line for supplying a power source to a fluorescence discharge tube, and the light emitter 3 and the wire 4 commonly construct a light emitter unit.
While the reflecting sheet 5 is bent at both end portions and housed in the rear face case 7, the sheet assumes a state where being open at bend portions in the rear face case 7 in a case where bending is insufficient or where a repulsive force against bending of the reflecting sheet 5 is strong. The wire 4 is necessary to be placed in a clearance between an end portion of the reflecting sheet 5 bent in the shape of an erected letter L and a side face of the rear face case, however, in a case where the bend portion of the reflecting sheet 5 contained in the rear face case 7 is open, a problem has arisen that a subsequent operation of housing the wire at a prescribed position is not easy.
Especially, in a case where a resin sheet is used as the reflecting sheet 5 for a purpose to attain a weight reduction, the resin sheet is a flexible material strong in restoring force against a bending pressure, so the reflecting sheet 5 is easy to open at a bend portion to deteriorate a work in housing the wire 4, having led to a difficulty in efficiently performing assembly.